On Tue, Jul 31, 2018 at 6:49 PM, Ming Lei <ming.lei@xxxxxxxxxx> wrote: > Hi, > > This patchset fixes one issue related with physical segment computation, > which is found by Mike. In case of dm-rq, the warning of 'blk_cloned_rq_check_limits: > over max segments limit' can be triggered easily. > > Follows the cause: > > 1) in IO fast path(blk_queue_split()), we always figure out physical segment number > no matter the flag of QUEUE_FLAG_NO_SG_MERGE is set or not. > > 2) only blk_recount_segments() and blk_recalc_rq_segments() uses the flag of > QUEUE_FLAG_NO_SG_MERGE, but the two are only called in some unusual > cases, such as request clone in dm-rq. > > 3) the above two computation don't match, and cause the warning of > "blk_cloned_rq_check_limits: over max segments limit". > > This patchset fixes this issue by killing the queue flag since it is basically > bypassed since v4.4, and no one complains that at all. Also multipage bvec will > come soon, and it doesn't make sense to keep QUEUE_FLAG_NO_SG_MERGE any more. > > > Ming Lei (3): > block: don't use bio->bi_vcnt to figure out segment number > block: kill QUEUE_FLAG_NO_SG_MERGE > block: kill BLK_MQ_F_SG_MERGE > > block/blk-merge.c | 39 +++++++-------------------------------- > block/blk-mq-debugfs.c | 2 -- > block/blk-mq.c | 3 --- > drivers/block/loop.c | 2 +- > drivers/block/nbd.c | 2 +- > drivers/block/rbd.c | 2 +- > drivers/block/skd_main.c | 1 - > drivers/block/xen-blkfront.c | 2 +- > drivers/md/dm-rq.c | 2 +- > drivers/md/dm-table.c | 13 ------------- > drivers/mmc/core/queue.c | 3 +-- > drivers/scsi/scsi_lib.c | 2 +- > include/linux/blk-mq.h | 1 - > include/linux/blkdev.h | 1 - > 14 files changed, 14 insertions(+), 61 deletions(-) > > Cc: Christoph Hellwig <hch@xxxxxx> > Cc: Mike Snitzer <snitzer@xxxxxxxxxx> > Cc: Kent Overstreet <kent.overstreet@xxxxxxxxx> Hello Guys, Ping... Thanks, Ming Lei
